Selected Research Projects

Ternary and quaternary coatings based on AlN

Thin nitride films such as TiN, TiAlN, CrAlN are most commonly used for wear protection. However, they cannot be used for applications, where optically transparency is required, as e.g. in protection of optical lenses.

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This project focuses on the preparation and characterization of novel oxygen-, silicon- and carbon-containing AlN-based coatings with improved oxidation resistance and tunable residual stress states. The properties can be tuned by the oxygen content (see schematics above).
Tetrahedral amorphous carbon coatings

We use an S3p HiPIMS industrial coating system donated to our laboratory by Oerlikon Surface Solutions's to develop smooth and wear-resistant coatings based on tetrahedral amorphous carbon (ta-C). A strategy developed on the basis of knowledge gained from atomistic simulations performed by our research partners of the Empa lab 205, we obtained coatings with a hardness above 50GPa with a low level of iresidual stress, a comparatively low elastic modulus, and a surface roughness below a few nanometers over areas of several microns. Interfacial gradient layers were designed to achieve excellent adhesion on different substrates. Our coatings reached almost the same hardness levels than the more conventional arc-deposited coatings but have a much better surface flatness and a lower elastic modulus. Further work will be aimed at the development of ta-C coatings with improved tribological properties following our strategies based on complex multilayer samples consisting of layers for lubrication, run-in, and designed wear and failure mechanisms.   

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HiPIMS metallization of polymer surfaces: Ti on PEEK for improved osseointegration

PEEK was identified as a candidate material for medical implants, because of its light-weight, its elastic modulus that is close to that of bone, its x-ray translucence, and compatibility with MRI. To promote osseo-integration the surface of the PEEK implant needs to be coated with titanium. For this we have used a home-built HiPIMS deposition system and achieved excellent Ti-PEEK adhesion and 3d-substrate conformity. Various implants have been coated with our process and successfully tested by various external research partners (e.g. Prof. PD S. Stübinger from the University of Basel).  Further work will address the transfer to the Ingenia coating system. 

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Selected and recently finished projects:

- Interfaces and interphases in nitride and carbide nanocomposite thin films

- Coatings for Precision Glass Molding

- Wear Resistant Coatings for Managed Thermal Conductivity

- HiPIMS for nanocomposite coatings

- Design of multifunctional nitride-based hard coatings

- Smart dielectric elastomer actuator for muscle-like actuators

A Coatings Competence Center for HiPIMS deposition
The Coatings Competence Center at Empa consists of presently three facilities to deposit thin films. One of them is an Ingenia S3p coater by Oerlikon Balzers. For further information please visit the Coating Competence Center's website.